KENNEDY SPACE CENTER, FL – Amidst the frenzy of ‘Sunshine State’ preparations for Cat 5 monster Hurricane Irma and quite dismal weather favorability odds, the skies surrounding the Florida Space Coast suddenly parted just in the nick of time enabling the Air Force’s secret military X-37B spaceplane to blast off this morning (Sept. 7) on a SpaceX Falcon 9 as the booster nailed another thrilling ground landing back at the Cape.

The SpaceX Falcon 9 roared to life at 10 a.m. EDT (1400 UTC) Thursday morning and soared aloft from seaside Launch Complex 39A on NASA’s Kennedy Space Center into nearly clear blue skies after the classified launch time was kept guarded until just 10 minutes before liftoff.

Due to the potential for catastrophic destruction from approaching Hurricane Irma this was the last chance for the X-37B to escape Florida to orbit before the Kennedy Space Center and Cape Canaveral Air Force Station almost certainly close on Friday, the backup launch opportunity.

The X-37B OTV spaceplane reached orbit as planned on SpaceX’s 13th launch of the year.

The nine Merlin 1D first stage engines ignited to generate a combined 1.7 million pounds of thrust fueled by liquid oxygen and RP-1 propellants, sending a huge exhaust plume billowing from behind as the rocket ascended off pad 39A and thundered aloft.

After first stage burnout and main engine cutoff the stages separated at T plus 2 min 26 seconds.

After successfully delivering the secret USAF mini-shuttle to orbit, SpaceX engineers completed the 2nd half of the double headed space spectacular when the Falcon 9 first stage booster successfully made a guided soft landing back at Cape Canaveral Air Force Station (CCAFS).

The boosters high speed descent generated multiple shockingly loud sonic booms as the 156-foot-tall first stage approached SpaceX’s dedicated Landing Zone-1 (LZ-1) on CCAFS that reverberated for dozens and dozens of miles across and beyond the Space coast region.

The mid-morning daylight first stage precision guided landing offered spectators a magnificent up close view of the rocket reusability technology envisioned by SpaceX’s billionaire CEO Elon Musk to drastically slash the high costs of launching people and payloads to space.

The X-37B launches vertically like a satellite but lands horizontally like an airplane and functions as a reliable and reusable space test platform for the U.S. Air Force.

The Boeing-built X-37B is processed for flight at the Kennedy Space Center, FL, using refurbished former NASA space shuttle processing facilities (OPFs) now dedicated to the reusable mini-shuttle, also named the Orbital Test Vehicle (OTV).

The last blastoff of the X-37B took place more than 2 years ago on May 20, 2015 when the OTV-4 mission launched on a ULA Atlas V on May 20, 2015 from Space Launch Complex-41 on Cape Canaveral Air Force Station.

After spending a record setting 718 days in orbit, the X-37B vehicle completed its fourth mission with a runway landing back at KSC’s Shuttle Landing Facility earlier this year on May 7, 2017.

Overall the OTV unmanned spacecraft have spent a total of 2,085 days in orbit.

The 11,000 pound (4990 kg) state-of-the art reusable OTV space plane is about a quarter the size of a NASA space shuttle. The vehicle measures 29 ft 3 in (8.9 m) in length with a wingspan of 14 ft 11 in (4.5 m).

The X-37B was originally developed by NASA but was transferred to the Defense Advanced Research Projects Agency (DARPA) in 2004.

Since then most but not all of the spaceplane’s goals have been shrouded in secrecy.

KENNEDY SPACE CENTER, FL – Although its far from sunny in the so called ‘Sunshine State’ the secret X-37B military mini-shuttle is set for a SpaceX blastoff and booster landing combo Thursday, Sept. 7 – even as the looming threat from Cat 5 Hurricane Irma forced Florida’s Governor to declare a statewide ‘State of Emergency.’

Launch preparations were in full swing today on Florida’s Space Coast for liftoff of the hi tech USAF X-37B reusable spaceplane- hoping to escape to orbit for the first time atop a SpaceX Falcon 9 rocket and just in the nick of time tomorrow, before the impending threat of monster storm Irma potentially lashes the launch pad at NASA’s Kennedy Space Center in the center of the states long peninsula.

I witnessed the entire SpaceX Falcon 9 rocket and payload stack being rolled horizontally up the incline to the top of Launch Complex 39A late this afternoon, Sept. 6, during our media visit for up-close camera setup.

Up close head on view of SpaceX Falcon 9 rocket rolling horizontally up incline at Launch Complex 39A at the Kennedy Space Center on 6 Sept. 2017. The rocket is being processed for liftoff of the X-37B OTV-5 mini-shuttle mission scheduled for Sept. 7, 2017. Credit: Ken Kremer/kenkremer.com

Rather remarkably the relatively dismal weather forecast has brightened considerably in the final hours leading to Thursday’s scheduled launch and the forecast heavy rain showers and thunder have dissipated in the time remaining between now and liftoff.

The X-37B reusable mini-shuttle is a secretive technology testing spaceplane flying on its fifth mission overall.

Up close side view of SpaceX Falcon 9 rocket and nose cone housing the X-37B OTV-5 spaceplane slated for liftoff from Launch Complex 39A at the Kennedy Space Center on Sept. 7, 2017. Credit: Ken Kremer/kenkremer.com

The path to launch was cleared following the successful engine test firing of the Falcon 9 first stage I witnessed late last week, Thursday afternoon, Aug. 30.

During the hold down static fire test all nine Merlin 9 stage engine were ignited and fired up to full throttle for several seconds. See my static fire story here.

SpaceX will offer their own live webcast beginning approximately 15 minutes before launch starting at about 9:35 a.m. EDT.

You can watch the launch live at NASA TV at the SpaceX hosted Webcast at – spacex.com/webcast

In the event of delay for any reason, the next launch opportunity is Friday, Sept 8 at approximately the same time and window.

However amidst the heavy duty Hurricane Irma preparations all around, nothing is certain. Local area schools in Brevard County have closed and local residents are preparing their homes and apartments to hunker down, buying food and essentials putting up storm shutters, topping off gas and energy supplies and more.

“If for any reason we cannot launch tomorrow we will reevaluate whether or not we can still support another attempt on Friday, said Wayne R. Monteith, Brig Gen, USAF, Commander, 45th Space Wing.

The weather forecast overall is about 50% chance of favorable conditions at launch time according to U.S. Air Force meteorologists with the 45th Space Wing Weather Squadron at Patrick Air Force Base. But the opportunity varies within the long window and the exact launch time is currently classified.

“Hurricane Irma is forecast to be approximately 900 miles southeast of the Spaceport during Thursday’s launch attempt, so while Irma certainly bears watching, the stalled boundary will be the main factor in Thursday’s weather,” noted the 45th Space Wing Weather Squadron.

The primary concerns on Sept. 7 are for cumulus clouds and for thick clouds in the flight path.

The odds drop to 40% favorable for the 24 hour scrub turnaround day on Friday, Sept 8

Everything is currently on track for Thursday’s launch of the 230 foot tall SpaceX Falcon 9 on the X-37B OTV-5 mission.

“The Air Force Rapid Capabilities Office is undergoing final launch preparations for the fifth mission of the X-37B Orbital Test Vehicle [OTV],” the Secretary of the Air Force Public Affairs announced. “The OTV is scheduled to launch on Sept. 7, 2017, onboard a SpaceX Falcon 9 launch vehicle.

The X-37B will be launched for the fifth time on the OTV-5 mission atop a SpaceX Falcon 9 on Sept. 7 from Launch Complex 39A on the Kennedy Space Center Florida into low Earth orbit.

The Boeing-built X-37B is processed for flight at KSC using refurbished NASA space shuttle processing facilities now dedicated to the reusable mini-shuttle, also known as the Orbital Test Vehicle (OTV). It launches vertically like a satellite but lands horizontally like an airplane and functions as a reliable and reusable space test platform for the U.S. Air Force.

The OTV-5 mission marks the first launch of an X-37B spaceplane by SpaceX.

All four prior OTV missions launched on the United Launch Alliance Atlas V and ended with runway landings in either California or Florida.

“The many firsts on this mission make the upcoming OTV launch a milestone for the program,” said Randy Walden, the director of the Air Force Rapid Capabilities Office.

“It is our goal to continue advancing the X-37B OTV so it can more fully support the growing space community.”

Ground landing of SpaceX Falcon 9 first stage at Landing Zone-1 (LZ-1) after SpaceX launched its 12th resupply mission to the International Space Station from NASA’s Kennedy Space Center in Florida from pad 39A at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Ken Kremer/Kenkremer.com

SpaceX will also attempt another land landing of the 156-foot-tall Falcon 9 first stage back at Landing Zone-1 (LZ-1) at the Cape.

The Falcon 9 first stage is equipped with a quartet of landing legs and grid fins to enable the rocket recycling plan.

Up close view of SpaceX Falcon 9 landing legs for the X-37B OTV-5 spaceplane slated for liftoff from Launch Complex 39A at the Kennedy Space Center on Sept. 7, 2017. Credit: Ken Kremer/kenkremer.com

This marks the 7th time SpaceX attempts a ground landing at the Cape.

The booster will touch down about 8 minutes after launch and generate multiple sonic booms screaming loudly across the surrounding region and beyond.

“The fifth OTV mission will also be launched into, and landed from, a higher inclination orbit than prior missions to further expand the X-37B’s orbital envelope.”

The daylight first stage precision guided landing should offer spectators a thrilling up close view of the rocket reusability technology envisioned by SpaceX’s billionaire CEO Elon Musk to drastically slash the high costs of launching to space.

Technicians work on the Air Force X-37B Orbital Test Vehicle 4, which landed at NASA’s Kennedy Space Center Shuttle Landing Facility in Florida May 7, 2017. Credit: Secretary of the Air Force Public Affairs.

The 11,000 pound (4990 kg) state-of -the art reusable OTV space plane is about a quarter the size of a NASA space shuttle. The vehicle measures 29 ft 3 in (8.9 m) in length with a wingspan of 14 ft 11 in (4.5 m).

The X-37B was originally developed by NASA but was transferred to the Defense Advanced Research Projects Agency (DARPA) in 2004.

Since then most but not all of the spaceplane’s goals have been shrouded in secrecy.

PLAYALINDA BEACH/KENNEDY SPACE CENTER, FL – Following a successful engine test firing of the Falcon 9 first stage late Thursday afternoon (Aug. 30), SpaceX is targeting a post Labor Day launch of the U.S. Air Force’s unmanned X-37B reusable mini-shuttle – a secretive technology testing spaceplane.

The brief but critical hold down engine test took place at 4:30 p.m. EDT (2030 GMT) Aug. 31 at Launch Complex 39A on NASA’s Kennedy Space Center – as witnessed live by myself and several spectators from nearby Playalinda Beach Causeway. See my photos herein.

Both SpaceX and the Air Force announced the target launch date after completion of the Aug. 31 engine test.

The routinely done static fire test and involves conducting a full launch dress rehearsal and countdown culminating with igniting all nine Merlin 1D first stage engines during a hold down test at the pad.

The Merlin’s generated a combined 1.7 million pounds of thrust and a huge exhaust plume billowing into the air from the north side flame trench during the test, which lasted several seconds.

The plume soon swirled overhead and dissipated about 10 minutes later. Ignition was accompanied by a loud roar we heard screaming out from the pad in all directions. A number of folks driving to and from Playalinda Beach had stopped to ask me what I was photographing prior to the test and stayed to witness the event.

The rocket will be lowered rolled back horizontally on the transporter erector into the SpaceX processing hangar and the spaceplane housed inside the payload fairing will be integrated on top. The full stack will then be rolled back out and erected at pad 39A.

The hold down test firing is carried out without the payload bolted on top inside the nose cone to keep it safe in the event of a catastrophic failure event such as occurred precisely 1 year ago – when a Falcon 9 blew up during fueling for similar engine test with the AMOS-6 satellite resulting in destruction of the rocket as well as the customers satellite hardware at pad 40.

The exact launch time had been a closely guarded secret – until this evening.

The X-37B launch is apparently lunchtime Thursday, September 7 at 12 PM – 12:01 PM, according to a Facebook post by the U.S. Air Force Space Command and the 45th Space Wing at Patrick Air Force Base, Fla., posted Friday evening.

“The Air Force Rapid Capabilities Office is undergoing final launch preparations for the fifth mission of the X-37B Orbital Test Vehicle [OTV],” the Secretary of the Air Force Public Affairs announced. “The OTV is scheduled to launch on Sept. 7, 2017, onboard a SpaceX Falcon 9 launch vehicle.

The X-37B will be launched for the fifth time on the OTV-5 mission atop a SpaceX Falcon 9 on Sept. 7 from Launch Complex 39A on the Kennedy Space Center Florida into low Earth orbit.

The Boeing-built X-37B is processed for flight at KSC using refurbished NASA space shuttle processing facilities now dedicated to the reusable mini-shuttle, also known as the Orbital Test Vehicle (OTV). It launches vertically like a satellite but lands horizontally like an airplane and functions as a reliable and reusable space test platform for the U.S. Air Force.

But in another first, the OTV-5 mission marks the first launch of an X-37B spaceplane by SpaceX.

All four prior OTV missions launched on the United Launch Alliance Atlas V and ended with runway landings in either California of Florida.

“The many firsts on this mission make the upcoming OTV launch a milestone for the program,” said Randy Walden, the director of the Air Force Rapid Capabilities Office.

“It is our goal to continue advancing the X-37B OTV so it can more fully support the growing space community.”

Blastoff of the X-37B spaceplane on United Launch Alliance (ULA) Atlas V rocket with the OTV-4 AFSPC-5 satellite for the U.S. Air Force at 11:05 a.m. EDT, May 20, 2015 from Space Launch Complex-41. Credit: Ken Kremer/kenkremer.com

After spending a record setting 718 days in orbit, the X-37B program completed its fourth mission with a runway landing back at KSC’s Shuttle Landing Facility on May 7, 2017. Overall OTV’s have spent a total of 2,085 days in orbit.

Also noteworthy is that OTV-5 will be launched into a higher inclination orbit compared to the prior four, serve as a technology testbed for multiple research payloads and will also somehow deploy several small satellites or cubesats.

“The fifth OTV mission continues to advance the X-37B’s performance and flexibility as a space technology demonstrator and host platform for experimental payloads,” the USAF said in a statement.

“This mission carries small satellite ride shares and will demonstrate greater opportunities for rapid space access and on-orbit testing of emerging space technologies. Building upon the fourth mission and previous collaboration with experiment partners, this mission will host the Air Force Research Laboratory Advanced Structurally Embedded Thermal Spreader payload to test experimental electronics and oscillating heat pipe technologies in the long duration space environment.”

SpaceX will also attempt another land landing of the 156-foot-tall Falcon 9 first stage back at Landing Zone-1 (LZ-1) at the Cape.

The Falcon 9 first stage is equipped with a quartet of landing legs and grid fins to enable the rocket recycling plan.

“The fifth OTV mission will also be launched into, and landed from, a higher inclination orbit than prior missions to further expand the X-37B’s orbital envelope.”

The daylight first stage precision guided landing should offer spectators a thrilling up close view of the rocket reusability technology envisioned by SpaceX’s billionaire CEO Elon Musk to drastically slash the high costs of launching to space.

Ground landing of SpaceX Falcon 9 first stage at Landing Zone-1 (LZ-1) after SpaceX launched its 12th resupply mission to the International Space Station from NASA’s Kennedy Space Center in Florida from pad 39A at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Ken Kremer/Kenkremer.com

The 11,000 pound (4990 kg) state-of -the art reusable OTV space plane is about a quarter the size of a NASA space shuttle. The vehicle measures 29 ft 3 in (8.9 m) in length with a wingspan of 14 ft 11 in (4.5 m).

The X-37B was originally developed by NASA but was transferred to the Defense Advanced Research Projects Agency (DARPA) in 2004.

Since then most but not all of the spaceplane’s goals have been shrouded in secrecy.

Blastoff of the X-37B spaceplane on United Launch Alliance (ULA) Atlas V rocket with the OTV-4 AFSPC-5 satellite for the U.S. Air Force at 11:05 a.m. EDT, May 20, 2015 from Space Launch Complex-41. Credit: Ken Kremer/kenkremer.comStory updated with additional details and photos[/caption]

The X-37B, a reusable Air Force space plane launched today, May 20, from Cape Canaveral, Florida, on its fourth mission steeped in mystery as to its true goals for the U.S . military and was accompanied by ten tiny cubesat experiments for NASA and the NRO, including a solar sailing demonstration test for The Planetary Society.

The military space plan successfully blasted off for low Earth orbit atop a 20 story United Launch Alliance (ULA) Atlas V rocket on the clandestine Air Force Space Command 5 (AFSPC-5) satellite mission for the U.S. Air Force Rapid Capabilities Office at 11:05 a.m. EDT (1505 GMT) today, May 20, from Space Launch Complex-41 on Cape Canaveral Air Force Station, Florida.

The weather cooperated for a spectacular liftoff from the Florida space coast, which was webcast live by ULA until five minutes after launch when it went into a communications blackout shortly after announcing the successful ignition of the Centaur upper stage.

The exact launch time was classified until it was released by the Department of Defense this morning. Early this morning the four hour launch window was narrowed down to two small windows of opportunity.

Among the experiments for the flight are 10 CubeSats housed in the Aft Bulkhead Carrier (ABC) located below the Centaur upper stage. Together they are part of the National Reconnaissance Office’s (NRO’s) Ultra Lightweight Technology and Research Auxiliary Satellite (ULTRASat). The 10 CubeSats in ULTRASat are managed by the NRO and NASA. They are contained in eight P-Pods from which they will be deployed in the coming days.

Also aboard the X-37B is a NASA materials science experiment called METIS and an advanced Hall thruster experiment. The Hall thruster is a type of electric propulsion device that produces thrust by ionizing and accelerating a noble gas, usually xenon.

Following primary spacecraft separation the Centaur will change altitude and inclination in order to release the CubeSat spacecraft.

They are sponsored by the National Reconnaissance Office (NRO) and NASA and were developed by the U.S. Naval Academy, the Aerospace Corporation, the Air Force Research Laboratory, California Polytechnic State University, and The Planetary Society.

LightSail marks the first controlled, Earth orbit solar sail flight according to the non-profit Planetary Society. Photons from the sun should push on the solar sails.

“The purpose of this LightSail demonstration test is to verify telemetry, return photos return and to test the deployment of the solar sails,” said Bill Nye, the Science Guy), and President of The Planetary Society, during the X-37B launch webcast.

“LightSail is comprised of three CubeSats that measure about 30 cm by 10 cm.”

“It’s smaller than a shoebox, everybody! And the sail that will come out of it is super shiny mylar. We’re very hopeful that the thing will deploy properly, the sunlight will hit it and we’ll get a push.”

The Boeing-built X-37B is an unmanned reusable mini shuttle, also known as the Orbital Test Vehicle (OTV) and is flying on the OTV-4 mission. It launches vertically like a satellite but lands horizontally like an airplane and functions as a reliable and reusable space test platform for the U.S. Air Force.

“ULA is honored to launch this unique spacecraft for the U.S Air Force. Congratulations to the Air Force and all of our mission partners on today’s successful launch! The seamless integration between the Air Force, Boeing, and the entire mission team culminated in today’s successful launch of the AFSPC-5 mission” said Jim Sponnick, ULA vice president, Atlas and Delta Programs.

The two stage Atlas V stands 206 feet tall and weighs 757,000 pounds.

The X-37B was carried to orbit by the Atlas V in its 501 configuration which includes a 5.4-meter-diameter payload fairing and no solid rocket motors. The Atlas first stage booster for this mission was powered by the RD AMROSS RD-180 engine generating some 850,000 pounds of thrust and fired for approximately the first four and a half minutes of flight. The Centaur upper stage was powered by the Aerojet Rocketdyne RL10C-1 engine.

The X-37B space plane was to separate from the Centaur about 19 minutes after liftoff. The Centaur continued firing separately with the CubeSat deployment, including the Planetary Society’s LightSail test demoonstration, into a different orbit later.

Overall this was ULA’s sixth launch of the 501 configuration the 54th mission to launch on an Atlas V rocket. This was also ULA’s fifth launch in 2015 and the 96th successful launch since the company was formed in December 2006.

The OTV is somewhat like a miniature version of NASA’s space shuttles.

Boeing has built two OTV vehicles. But it is not known which of the two vehicles was launched today.

Altogether the two X-37B vehicles have spent a cumulative total of 1367 days in space during the first three OTV missions and successfully checked out the vehicles reusable flight, reentry and landing technologies.

The 11,000 pound (4990 kg) state-of -the art reusable OTV space plane was built by Boeing and is about a quarter the size of a NASA space shuttle. It was originally developed by NASA but was transferred to the Defense Advanced Research Projects Agency (DARPA) in 2004.

All three OTV missions to date have launched from Cape Canaveral, Florida and landed at Vandenberg Air Force Base, California. Future missions could potentially land at the shuttle landing facility at the Kennedy Space Center, Florida.

The first OTV mission launched on April 22, 2010, and concluded on Dec. 3, 2010, after 224 days in orbit.

The following flights were progressively longer in duration. The second OTV mission began March 5, 2011, and concluded on June 16, 2012, after 468 days on orbit. The third OTV mission launched on Dec. 11, 2012 and landed on Oct. 17, 2014 after 674 days in orbit.

Among the primary mission goals of the first three flights were check outs of the vehicles capabilities and reentry systems and testing the ability to send experiments to space and return them safely. OTV-4 will shift somewhat more to conducting research.

“We are excited about our fourth X-37B mission,” Randy Walden, director of the USAF’s Rapid Capabilities Office, said in a statement. “With the demonstrated success of the first three missions, we’re able to shift our focus from initial checkouts of the vehicle to testing of experimental payloads.”

Launch of the X-37B spaceplane on a United Launch Alliance (ULA) Atlas V rocket with the AFSPC-5 satellite for the U.S. Air Force at 11:05 a.m. EDT, May 20, 2015 from Space Launch Complex-41. Credit: ULAA United Launch Alliance (ULA) Atlas V rocket successfully launched the AFSPC-5 satellite for the U.S. Air Force at 11:05 a.m. EDT today, Wednesday, May 20, 2015 from Space Launch Complex-41. Credit: ULA

Fourth flight of the secretive U.S. Air Force X-37B Orbital Test Vehicle is set for blastoff on May 20, 2015 from Cape Canaveral, Florida. Photo: Boeing
Story updated with further details and photos[/caption]

All systems are currently “GO” for the fourth launch of the US Air Force’s secretive unmanned, X-37B military space plane this Wednesday, May 20, on a flight combining both US national security experimental payloads as well as civilian science experiments sponsored by NASA, US Universities, commercial companies, and the solar sailing LightSail test from the Planetary Society.

LightSail marks the first controlled, Earth orbit solar sail flight according to the non-profit Planetary Society. It will launch as a separate cubesat experiment. NASA also has an advanced materials science experiment flying aboard the robotically controlled X-37B.

The X-37B is set for blastoff atop a two stage United Launch Alliance (ULA) Atlas V 501 rocket on the AFSPC-5 mission under contract for the U.S. Air Force Rapid Capabilities Office.

The Boeing-built X-37B is an unmanned reusable mini shuttle, also known as the Orbital Test Vehicle (OTV) and is flying on the OTV-4 mission. It launches vertically like a satellite but lands horizontally like an airplane.

Although virtually all the goals of the X-37B program are shrouded in secrecy, some details on the national security objectives have emerged and there are several unclassified experiments flying along as secondary objectives on the rocket and space plane, among them are experiments for NASA and the Planetary Society.

LightSail launches aboard the X-37B on May 20, 2015. Credit: The Planetary Society

Among the primary mission goals of the first three flights were check outs of the vehicles capabilities and reentry systems and testing the ability to send experiments to space and return them safely. OTV-4 will shift somewhat more to conducting research.

“We are excited about our fourth X-37B mission,” Randy Walden, director of the USAF’s Rapid Capabilities Office, said in a statement. “With the demonstrated success of the first three missions, we’re able to shift our focus from initial checkouts of the vehicle to testing of experimental payloads.”

Liftoff will take place from Space Launch Complex (SLC)-41 at Cape Canaveral Air Force Station, Florida, at some point during a four hour launch period that opens at 10:45 a.m. EDT and extends until 2:45 p.m. EDT on May 20.

ULA announced that the Launch Readiness Review was completed on Monday and everything is progressing normally toward the AFSPC-5 launch. The rocket is fully assembled and the space plane is encapsulated inside the 5 meter diameter payload fairing. It rolled out to the pad today, Tuesday, May 19.

The ULA webcast begins at 10:45 a.m. EDT on May 20. The precise launch time is classified and won’t be announced until Wednesday morning.

The weather prognosis has improved markedly to a 60 percent chance of favorable weather conditions, up from only a 40 percent chance this past weekend.

The primary weather concerns are for violations of the launch weather rules related to cumulus clouds, surface electric fields, anvil clouds and lightning.

Launch officials are hopeful that acceptable launch conditions will occur sometime during the lengthy four hour launch window.

In the event of a 24 hour delay due to weather or technical issues, the outlook drops to only a 30% chance of favorable weather conditions during the launch window.

The OTV is somewhat like a miniature version of NASA’s space shuttles. Boeing has built two OTV vehicles.

2nd X-37B Orbital Test Vehicle Successfully Completes 1st Flight by landing at Vandernberg AFB, Calif., on June 16, 2012. It is designed to be launched like a satellite and land like an airplane. Credit: Boeing.

Altogether the two X-37B vehicles have spent a cumulative total of 1367 days in space during the first three OTV missions and successfully checked out the vehicles reusable flight, reentry and landing technologies.

The reusable space plane is designed to be launched like a satellite and land on a runway like an airplane and a NASA space shuttle. The X-37B is one of the newest and most advanced reentry spacecraft.

The 11,000 pound (4990 kg) state-of -the art reusable OTV space plane was built by Boeing and is about a quarter the size of a NASA space shuttle. It was originally developed by NASA but was transferred to the Defense Advanced Research Projects Agency (DARPA) in 2004.

All three OTV missions to date have launched from Cape Canaveral, Florida and landed at Vandenberg Air Force Base, California. Future missions could potentially land at the shuttle landing facility at the Kennedy Space Center, Florida.

The first OTV mission launched on April 22, 2010, and concluded on Dec. 3, 2010, after 224 days in orbit.

The following flights were progressively longer in duration. The second OTV mission began March 5, 2011, and concluded on June 16, 2012, after 468 days on orbit. The third OTV mission launched on Dec. 11, 2012 and landed on Oct. 17, 2014 after 674 days in orbit.

The OTV-4 mission will shift its focus at least somewhat from tests of the vehicles performance to more on science experiments both with extra capacity available on the Atlas V rocket and payload space aboard the X-37B itself.

“We’ll continue to evaluate improvements to the space vehicle’s performance, but we’re honored to host these collaborative experiments that will help advance the state-of-the-art for space technology

Among the experiments for the flight are 10 CubeSats. They will launch in the Aft Bulkhead Carrier (ABC) located below the Centaur upper stage that contains eight P-Pods to release the CubeSats.

Following primary spacecraft separation the Centaur will change altitude and inclination in order to release the CubeSat spacecraft, ULA said in a statement.

They are sponsored by the National Reconnaissance Office (NRO) and NASA and were developed by the U.S. Naval Academy, the Aerospace Corporation, the Air Force Research Laboratory, California Polytechnic State University, and Planetary Society.

NASA is also flying an advanced materials science payload on the X-37B called the Materials Exposure and Technology Innovation in Space (METIS) investigation that will build on more than a decades worth of materials science research on the International Space Station (ISS) research.

“By flying the Materials Exposure and Technology Innovation in Space (METIS) investigation on the X-37B, materials scientists have the opportunity to expose almost 100 different materials samples to the space environment for more than 200 days. METIS is building on data acquired during the Materials on International Space Station Experiment (MISSE), which flew more than 4,000 samples in space from 2001 to 2013, NASA said in a statement.

“By exposing materials to space and returning the samples to Earth, we gain valuable data about how the materials hold up in the environment in which they will have to operate,” said Miria Finckenor, the co-investigator on the MISSE experiment and principal investigator for METIS at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

“Spacecraft designers can use this information to choose the best material for specific applications, such as thermal protection or antennas or any other space hardware.”

Recovery crew members process the X-37B Orbital Test Vehicle at Vandenberg Air Force Base after completing 674 days in space. A total of three X-37B missions have been completed, totaling 1,367 days on orbit. Photo: BoeingWatch cool landing video below[/caption]

The US Air Force’s unmanned, X-37B military space plane made an autonomous runway landing on Friday, Oct. 17, at Vandenberg Air Force Base, Calif., concluding an orbital test flight nearly two years in duration on a record breaking mission whose goals are shrouded in secrecy.

The Boeing-built X-37B, also known as the Orbital Test Vehicle (OTV), successfully fired its baking thrusters, plunged through the atmosphere, endured scorching re-entry heating and safely rolled to touch down on Vandenberg Air Force Base at 9:24 a.m. PDT Friday, concluding a clandestine 674-day experimental test mission for the U.S. Air Force Rapid Capabilities Office.

This was the third flight of an X-37B OTV vehicle on a mission known as OTV-3.

“I’m extremely proud of our team for coming together to execute this third safe and successful landing,” said Col Keith Balts, 30th Space Wing commander, in a statement.

“Everyone from our on console space operators to our airfield managers and civil engineers take pride in this unique mission and exemplify excellence during its execution.”

Nothing is known about the flights objectives or accomplishments beyond testing the vehicle itself.

The OTV is somewhat like a miniature version of NASA’s space shuttles. Boeing has built two OTV vehicles.

The reusable space plane is designed to be launched like a satellite and land on a runway like an airplane and a NASA space shuttle. The X-37B is one of the newest and most advanced reentry spacecraft.

A third mission of the Boeing-built X-37B Orbital Test Vehicle was completed on Oct. 17, 2014, when it landed and was recovered at Vandenberg Air Force Base, Calif, following a successful 674-day space mission. Photo: Boeing

OTV-3 also marked the first reflight of an OTV vehicle, to test its re-usability.

Among the primary mission goals of the first two flights were check outs of the vehicles capabilities and reentry systems and testing the ability to send experiments to space and return them safely.

It is not known if the X-37B conducted reconnaissance activities during the test flights. It does have the capability to deploy satellites in space.

All three OTV missions have launched from Cape Canaveral and landed at Vandenberg.

The first OTV mission launched on April 22, 2010, and concluded on Dec. 3, 2010, after 224 days in orbit. The second OTV mission began March 5, 2011, and concluded on June 16, 2012, after 468 days on orbit.

“The 30th Space Wing and our mission partners, Air Force Rapid Capabilities Office, Boeing, and our base support contractors, have put countless hours of hard work into preparing for this landing and today we were able to see the culmination of that dedication,” said Balts.

The 11,000 pound state-of -the art reusable OTV space plane was built by Boeing and is about a quarter the size of a NASA space shuttle. It was originally developed by NASA but was transferred to the Defense Advanced Research Projects Agency (DARPA) in 2004.

Altogether, the OTV vehicles have spent 1,334 days in Earth orbit.

The OTV’s can stay on orbit far longer than NASA’s shuttles since their power is supplemented by solar panels deployed from the vehicles open cargo bay.

“The landing of OTV-3 marks a hallmark event for the program” said the X-37B program manager. “The mission is our longest to date and we’re pleased with the incremental progress we’ve seen in our testing of the reusable space plane. The dedication and hard work by the entire team has made us extremely proud.”

“With a program total of 1,367 days on orbit over three missions, these agile and powerful small space vehicles have completed more days on orbit than all 135 Space Shuttle missions combined, which total 1,334 days,” said Ken Torok, Boeing director of Experimental Systems, in a statement.

Recovery crew members process the X-37B Orbital Test Vehicle at Vandenberg Air Force Base after completing 674 days in space. A total of three X-37B missions have been completed, totaling 1,367 days on orbit. Photo: Boeing

“The X-37B is the newest and most advanced re-entry spacecraft. Managed by the Air Force Rapid Capabilities Office, the X-37B program performs risk reduction, experimentation and concept of operations development for reusable space vehicle technologies,” according to an Air Force statement.

The Air Force says that the next X-37B launch on the OTV-4 mission is due to liftoff from Cape Canaveral sometime in 2015.

US Air Force X-37B OTV-2 mini space shuttle is encapsulated in 5 meter payload fairing and bolted atop an Atlas 5 rocket at Pad 41 at Cape Canaveral Air Force Station, Florida prior to 5 March 2011 launch. This up close view of the nose cone holding the secretive X-37B shows the umbilical line attachments. Credit: Ken Kremer

Image Caption: 2nd X-37B Orbital Test Vehicle Successfully Completes 1st Flight by landing at Vandernberg AFB, Calif., on June 16, 2012. The record setting mission lasted 469 days in earth orbit. Designed to be launched like a satellite and land like an airplane, the second X-37B Orbital Test Vehicle, built by Boeing for the United States Air Force’s Rapid Capabilities Office, is an affordable, reusable space vehicle. Credit: Boeing.See landing video below

The 2nd of the US Air Force’s top secret X-37B unmanned, reusable mini shuttles safely landed on Saturday, June 16, at 5:48 a.m. Pacific local time at Vandenberg Air Force Base, California to conclude a record setting classified 469 day experimental test flight in Earth orbit.

This was the first flight of OTV-2 and the second flight of the military’s classified X-37B Orbital Test Vehicle (OTV) test program for the U.S. Air Force Rapid Capabilities Office.

The reusable space plane is designed to be launched like a satellite and land on a runway like an airplane and NASA space shuttle. The X-37B is one of the newest and most advanced reentry spacecraft.

Here is the YouTube landing video released by the US Air Force:

OTV-2 was launched atop a United Launch Alliance Atlas V booster from Cape Canaveral Air Force Station, Fla., on March 5, 2011.

About 18 minutes after launch, the Air Force imposed a news blackout on the classified mission. Details about the cargo and experiments loaded aboard the Air Force orbital space plane are shrouded behind a veil of military security.

It is not known if the X-37B conducted reconnaissance activities during the test flight. It does have the capability to deploy satellites in space

The Air Force says the primary mission goal was to check out the vehicles capabilities and testing the ability to send experiments to space and return them safely.

Image caption: Top secret Air Force X-37B OTV mini space shuttle is encapsulated in 5 meter payload fairing and bolted atop an Atlas 5 rocket at Pad 41 at Cape Canaveral Air Force Station, Florida prior to 5 March 2011 launch. This up close view of the nose cone holding the classified X 37-B shows the umbilical line attachments. Credit: Ken Kremer

The mission duration of well over one year far exceeded the 220-day mission duration of the first OTV craft and tested additional capabilities. Two OTV vehicles have been built by Boeing. The first craft, known as OTV-1, was the United States’ first unmanned vehicle to return from space and land on its own.

Previously, NASA space shuttles piloted by astronauts were the only space vehicles that had demonstrated the capability of returning to Earth and being reused.

“The vehicle was designed for a mission duration of about 270 days,” said Lt. Col. Tom McIntyre, the X-37B program manager in an Air Force statement. “We knew from post-flight assessments from the first mission that OTV-1 could have stayed in orbit longer. So one of the goals of this mission was to see how much farther we could push the on-orbit duration.”

The 11,000 pound state-of -the art reusable OTV space plane was built by Boeing and is about a quarter the size of a NASA space shuttle. It was originally developed by NASA but was transferred to the Defense Advanced Research Projects Agency (DARPA) in 2004.

“With the retirement of the space shuttle fleet, the X-37B OTV program brings a singular capability to space technology development,” McIntyre said. “The return capability allows the Air Force to test new technologies without the same risk commitment faced by other programs”

Among the cutting-edge technologies tested were the auto de-orbit capability, thermal protection tiles, and high-temperature components and seals.

“The X-37B’s advanced thermal protection and solar power systems, and environmental modeling and range safety technologies are just some of the technologies being tested,” said McIntyre. “Each mission helps us continue to advance the state-of-the-art in these areas.”

“We look forward to the second launch of OTV-1 later this year and the opportunity to demonstrate that the X-37B is an affordable space vehicle that can be repeatedly reused,” said Paul Rusnock, Boeing vice president of Government Space Systems.

The United States Air Force’s second flight of the X-37B – is headed into extra innings. Known as the Orbital Test Vehicle 2 (OTV-2) this robotic mini space shuttle launched from Cape Canaveral Air Force Station’s Space Launch Complex 41 (SLC-41) on Mar. 5, 2011. Although the U.S. Air Force has kept mum regarding details about the space plane’s mission – it has announced that the OTV-2 has exceeded its endurance limit of 270 days on orbit as of the end of November.

The OTV is launched atop a United Launch Alliance (ULA) Atlas V 501 rocket. The space plane is protected within a fairing until it reaches orbit. After separation, the diminutive shuttle begins its mission.

OTV mission USA-226, as it is officially known, is by all accounts going smoothly and the spacecraft is reported to be in good health. The U.S. Air Force has not announced when OTV-2 will be directed to land.

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The fact that the space plane will continue to orbit beyond what its stated limits are highlights that the OTV has greater capabilities than what was officially announced. The first OTV flight launched in April of 2011 and landed 224 days later at Vandenberg Air Force Base in California. The U.S. Air Force is undoubtedly being more judicious with fuel stores on board the robotic spacecraft, allowing for a longer duration flight.

Much like NASA’s retired fleet of space shuttle orbiters, the OTV has a payload bay that allows for payloads and experiments to be conducted on-orbit. What payloads the U.S. Air Force has had on either mission – remains a secret.

Boeing has announced that the X-37B could be modified to conduct crewed missions to and from orbit. Tentatively named the X-37C, this spacecraft would be roughly twice the size of its unmanned cousin. If this variant goes into service it would be used to transport astronauts to and from the orbiting International Space Station (ISS).

The X-37B has become a bit controversial of late. Members of the Chinese press have stated that the space plane raises concerns of an arms race in space. Xinhua News Agency and China Daily have expressed concern that the OTVs could be used to deliver weapons to orbit. The Pentagon has flatly denied these allegations. The clandestine nature of these flights have led to a wide variety of theories as to what the OTVs have been used to ferry to orbit.